The Australian Chamber of Commerce and Industry (ACCI) says the real advantage of the early announcement is that the final quarter of the year will not be interrupted by the politics of the campaign.

"With the early election announcement, it would be the business community's preference for an early disclosure of the policies, the programs, and the vision of both the Opposition and the Government for Australia's economy to become stronger and more competitive," ACCI's Peter Anderson told reporters in Canberra.

"We want a bidding war between Julia Gillard and Tony Abbott and their parties over who can make the economy more prosperous, more competitive and create more jobs by supporting the private sector."

3:05pm:

Opposition Leader Tony Abbott has called a press conference for 3.40pm (AEDT).

2:55pm:

The federal Member for O'Connor, Tony Crook, says while he is surprised by the Government's early announcement of the election date, he thinks it creates certainty.

"I think in many respects it's a good thing. It gives us some certainty about where we're heading," the WA Nationals MP said.

"People can plan, people can make up their own minds about why it has been done.

"For me, it's business as usual."

2:47pm:

Antony Green has listed every electorate on his blog and what the margins are.

Independent MP Andrew Wilkie says he will recontest his Hobart seat of Denison, which he holds by a 1.2 per cent margin on two-party preferred basis.

"My best re-election strategy has always been, and continues to be, to just do my job well."

He says setting an election date early will be good for businesses and investors, but it will be wasted if it leads to a very long election campaign.

"There's still a significant period of this parliament left to run and that demands the Government stay focused on running the country and the Opposition on holding the Government to account."

2:32pm:

Greens leader Christine Milne says the Prime Minister's office gave her a half-hour heads up that Ms Gillard would be announcing the election date in her speech today.

Senator Milne says now's a good time to introduce three-year fixed terms, so that future elections will always be held in the second week of September.

"Wouldn't that be a great thing for the Australian people, so that we didn't have all the game-playing that has gone on in the past," Senator Milne told reporters in Melbourne.

She wants Ms Gillard and Mr Abbott to agree to the change.

2:27pm:

Independent senator Nick Xenophon tells Lyndal Curtis that the PM has "put all of us out of our misery by announcing the election date".

"I think it's good for there to be some advanced notice. It's good for independents and minor parties, I guess, but it also gives some certainty rather than having months of speculation as to when the election will be held.

"We now know the date and I think that's probably a good thing in the context of the marathon that now awaits us."

Senator Xenophon's term expires in 2014 and he says that "I'll announce what I'm doing in the next few weeks."

Independent MP Tony Windsor says he intends to contest the election. The Coalition has preselected independent NSW MP Richard Torbay as its candidate for Mr Windsor's seat of New England. Mr Windsor says he's not sure whether he'll win the contest, but adds that "the mood feels pretty good out there".

Liberal MP Josh Frydenberg, who is Jewish, has criticised the decision to hold the election on September 14 - which is Yom Kippur, the holiest day of the year for Jewish people.

"In choosing the 14th of September... she disenfranchises many Jewish Australians, it's incredibly sloppy on her part, it's a knee-jerk reaction to pressure that she's coming under within the Labor party," he told ABC News.

"It's going to be very difficult for Jewish Australians to participate in election day activities - they spend most of the day in prayer and also they fast."

Ms Gillard says she understands the significance of the day for the Jewish community, but says there are only a limited number of days on which to hold an election because of international commitments and football finals.

She says anyone who cannot vote on that day has the option of casting a pre-poll ballot.

1:57pm:

Greens leader Christine Milne has called a media conference for 2:20pm where she will call for fixed-term elections.

Ms Gillard expects there'll be some debate about the idea, but says it's not a priority for her.

"For me, it's not the upper most policy matter on my mind. I'm very focused on jobs, opportunity, fairness, on getting done the big things that will shape this nation for the future."

1:49pm:

According to the ABC's election analyst Antony Green, the last time a federal election was held in September was in 1946. The most common month for a federal poll is December. Constitutionally speaking, the last date on which this year's election could have been held was November 30.

1:36pm:

The Prime Minister says she announced the election date early so that the nation can focus on "policies, not petty politics".

The move will add pressure on the Coalition to release more of its policies early.

On Sunday, Opposition Leader Tony Abbott launched a "mini-campaign" and released a 50-page policy document.

Ms Gillard used the speech to the National Press Club to lay the groundwork for an election year battle focused on the economy, arguing that a strong economy is necessary to ensure fairness in education and disability services.

One of the key planks of the Government's 2013 agenda will be overhauling how the education system is funded, in line with the Gonski report.

In today's speech, she's described it as a "moral cause - a crusade".

1:20pm:

Independent MP Tony Windsor says the early announcement of the election date will help provide certainty and stability to the community, but also most importantly to businesses.

"Today's announcement will remove the media speculation of a date and reduce the space devoted to the hype surrounding the choice of a date usually until six weeks before an election.

"Putting paid to this practice will encourage the media to present the policy choices allowing Australians to consider their options over a longer period of time."

Ms Gillard says she spoke with Mr Windsor and Mr Oakeshott by phone, to advise them of when the election would be held.

1:15pm:

Antony Green on Twitter:

@AntonyGreenABC : PM copies NZ PM John Key by announcing election day more than half a year in advance ... 9 months notice of the election date. Longer than the 3 months Menzies gave in 1958 and 1961.

1:12pm:

Independent MP Rob Oakeshott says the announcement of the election date will allow the Parliament to run its full term without ongoing speculation.

In a statement, he said:

"There are nine more important sitting weeks of this Parliament, and the challenge now is for this time to be spent focused on the ongoing policy and reform detail - such as the Gonski reforms in education - that many Australians want to see delivered before the year is over.

"Campaigning and electioneering throughout these nine final sitting weeks, while this detailed work is being done, should be seen for what it is - serving the interests of political parties, not the interests of the nation."